Polycarbonate-series resins have good dimensional stability, good mechanical characteristics and good thermal properties (heat resistance) and therefore are in wide industrial use (parts of electric or household electric appliances, precision instruments, OA equipment, medical instruments, household utensils, sports equipment, etc.). However, polycarbonate-series resins are poor in chemical resistance and processability (moldability, platability), in particular flow characteristics, besides being relatively expensive. Therefore, a number of polymer blends thereof with other thermoplastic resins have been developed. There is disclosed that, in Japanese Patent Publication No. 15225/1963 (JP-B-38-1525), Japanese Patent Publication No. 71/1964 (JP-B-39-71), Japanese Patent Publication No. 11496/1967 (JP-B-42-11496), and Japanese Patent Publication No. 11142/1976 (JP-B-51-11142), the moldability of polycarbonate resin can be improved and the thickness-dependency of impact strength is lowered by blending acrylonitrile-butadiene-styrene copolymers (ABS resins) or methyl methacrylate-butadiene-styrene copolymers (MBS resins) among thermoplastic resins with polycarbonate-series resins. For the purpose of flowability or fluidity improvement and cost reduction, such polymer blends are widely used in automotive, OA equipment, electronic and electric fields, among others.
However, polymer blends of a polycarbonate-series resin and a rubber-modified polystyrene resin such as an impact-resistant styrenic resin (high impact polystyrene) are poor in compatibility, mechanical characteristics, heat-stability and impact resistance, and therefore are of little present use.
In Japanese Patent Application Laid-Open No. 197554/1991 (JP-A-3-197554), there is disclosed that the compatibility of an aromatic polycarbonate-series resin with a polyphenylene ether resin can be enhanced by adding a compatibilizing agent and an elastomer component, hence the impact-strength of molded articles can be improved.
Moreover, in Japanese Patent Application Laid-Open No. 54160/1973 (JP-A-48-54160) and No. 107354/1974 (JP-A-49-107354), there is disclosed compositions of an aromatic polycarbonate and a polyester-series resin. These compositions are, however, poor in melt stability and its softening point lowers when the compositions are residence in molding process. In Japanese Patent Application Laid-Open No. 247248/1990 (JP-A-2-247248) and No. 100400/1997 (JP-A-9-100400), attempts at solving these problems have been made, but the effects are still unsatisfactory.
In Japanese Patent Application Laid-Open No. 131056/1987 (JP-A-62-131056), there is disclosed that the surface hardness can be improved by employing a composition of an aromatic polycarbonate and an acrylic resin, hence the abrasion resistance can be improved. The combination of these resins, however, is still poor in compatibility, and effects of improvement in abrasion resistance are not satisfactory.
On the other hand, in the fields of OA equipment and household electric appliances, among others, synthetic resin materials are required to have flame retardancy, and halogen-containing flame retardants, namely bromine- or chlorine-containing ones, are generally used as fire or flame retardants to be added externally. Such flame retardants can provide relatively high fire retardancy but tend to generate corroxive or toxic gases upon processing or combustion. In view of increasing interest in environmental problems in recent years, it is desired that flame-retardant resins free of chlorine- or bromine-containing halogen compounds be developed as means of solving the drawbacks mentioned above.